Bushing and slip assembly



Jan. 17, 1939.

D. I .DRlscQLL B/USHING ANMDSVLIP 'ASSEMBLY Filed pril 24, 1956 2 Sheets-Sheet 1 Jan. 17, 1939. 4 D. DRlscoLL 2,144,146 i BUSHING AND "SLIP ASSEMBLY Filed April 24, 1956 2 Sheets-Sheet 2 Patented Jan. 1.7, 1939 UNiTE-DsTATEs PATENT OFFICE N RUSHING` Aillills ASSEMBLY Dennis L. Driscoll, Los Angeles, Calif., assignerto Lawrence F. Baas'h, Los Angeles, Calif.

Application Apriizi, 193s, serial No. 76,196

' 4 Claims.

This invention relates to well drilling equipment and relates more particularly to a bushing and slip assembly foruse in the rotary table of a well drilling rig.` `A general object of this invention is to provide a practical, particularly effective bushing and for a rotary table.

improved and slip assembly ceiving pipe gripping slips and emb odying simple,

dependable means for limiting the downward movement of the slips in the slots.

Another object of the invention is to provide a bushing of the character mentionedin which the means for limiting the downward movement of the slips in the slots serve to c ends of the slots to prevent the lose the lower pipe land the` coupling parts on the pipe from entering'the slots and from wearing away or breaking `the parts dening the slots.

Another object of the invention is to a bushing and slip assemblyv of the character mentioned embodying slips having novel and par-` ticularly effective pipe engaging parts or shoes. A further object of the invention is to provide arotary table bushing divided into two sections? in a plane of division spaced from its vertical axis whereby one section central is larger than the other, the larger section having two slots for receiving slips and the smaller section having one slip receiving slot.

The various objects and features of my inven` tion will be fullyunderstood from detailed description of typical pr the following eferred forms and applications of the invention, throughout which description reference is made tothe ac companying drawings, in which:

Fig. 1 is a top or plan viewof one embodiment of the invention illustrating thev slipsin position in the bushing and engaging a pipe. FigfZ is an enlarged fragmentary vertical detailed sectional view taken as indicated by line 2 2 on Fig. 1. Fig. 3 is a transverse fragmentary detailed sectional view taken as indicated byline 3-3 on Fig. 2." Fig. 4 is a fragmentary transversede` tailed sectional view taken substantially as indicated byline `4--4` on Fig. 2. Fig. 5

is an elevation` vieviT of the inner side of oneof the slips removed from the bushing landlilig. 6isy ato provide 1 M p or plan View of another form of the-invention.-

The embodiment of the invention illustrated in Figs. l to 5, inclusive, of the drawings includes, generally, a sectional bushing I having slots II in its interior, slips I2 for arrangement in the slots I I, and means I3 for limiting the downward 5 movement of the slips I2 in the slots II.

The bushing I0 is intended for arrangement in the rotary table of a well drilling rig. In accordance with the invention the bushing IIJ may be designed for use in various types and lo forms of rotary tables. In the particular case illustrated in the drawings the bushing I0 is employed in a rotary table T having a round vertical opening I4 and a polygonal or square recess I5 in the upper end of the opening I4. The l5 bushing IIJ fits in the opening I4 and is provided with a square liange I6 cooperating with the recess I5. The cooperation of the flange I6 with the recess I5 causes the bushing I0 to rotate with the table T. The bushing I0 is provided with a central opening I'l for receiving and passing the pipe P and other drilling equipment. In accordance with the invention, the opening I1 is` cylindrical or of substantially uniform diameter throughout its length. The bushing I0 is preferably sectional to facilitate its assembly in the table T. In the form of the invention being described the bushing I0 is divided or separated at a diametric vertical plane IB into two equal sec tions A and B. p

The slots III are provided in the wall of the opening I1 to receive the s1ipsI2. In the preferred arrangement illustrated there are three equally spaced slots I I. The slots I I being equally spaced are substantially 120 apart. In the form of the invention being described there is one slot` II in each section A and B and the third slot II has its vertical or longitudinal center in the plane of separation I8 so that it is formed in adjacent parts of the two bushing sections A and B. 'I'hel slots I I are preferably identical in size and shape. The shape and proportioning of the slots II are features of the invention. The slots II are elongated vertically and preferably extend between the upper and lower ends of the bushing opening I1. In accordance with the invention'the slots I I have flat parallel side walls and inclined inner walls` 20. In the particular case illustrated the inclined walls are flat, it being understood that these walls 20 may be convexed or concavedif desired. The slot walls 20 are inclined downwardly and inwardly relative to the central ver-- tical axis of the bushing opening I'I. The walls 20 are uniformly pitched and extend throughout the major portion of the vertical extent or thick- ,through the bushing I0. There is a slip I2 for arrangement in each slot II and the three slips "are preferably alike or identical. Each slip I2 includes a body 2| having fiat parallel sides 22 j and an inclined inner surface 23. The surfaces 23 are fiat and of substantially the 'same inclinaltion as the slot walls 2D to have even full cooperation therewith. The sides 22 of the slip bodies 2| are adapted to cooperatewith or bear on the side walls of the slots I I. The slip bodies 2| are sufiiciently long to extendv from adjacent the lower ends of the slots I I to points above the upper surface of the bushing IB. The slip bodies 2| are hollow or provided with chambers 24 to be'light in weight and readily handled. Suitable handlesV r25 are provided on the slips I2. The handles 25 may be of any suitable construction and may be secured to the slip bodies 2| as found most desirable. In the' case illustrated in the drawings recesses 26 are provided in the upper ends of the slip bodies 2| and pivot pins 21 extend through the recesses 26 to pivotally secure rthe handles 25 to the bodies of the slips. The handles 25 are adapted to engage the slip bodies 2| at the rear walls of the recesses 26 as shown at 28 to be in position for ready engagement or grasping. Lugs 29 may be provided on the handles 25 adjacent the pivot pins 21 to limit the inward swinging or pivoting of the handles.

vThe invention provides wear taking liners or shoes 30 on the slip bodies 2 I. The shoes 30 are removably secured to the bodies of the slips II. Longitudinal dove-tailed grooves 3| are provided in the inner vertical sides of the slip bodies 2|. Dove-tailed tongues 32 are provided on the shoes 30 to cooperate with the grooves 3|. The shoes y 30 are adapted to fully and evenly bear on` the inner sides of the slip bodies 2| and cooperation of the grooves 3| and tongues 32 assists in positioning and retaining the shoes in place. The lower walls 33 ofthe grooves 3| slope upwardly and inwardly and the lower ends of the tongues 32 are correspondingly inclined. rThe cooperation of the lower ends of the tongues 32 with the walls 33 assists in locking the shoes 30 on the slip bodies. Rods or rivets 34% extend through transverse or horizontal openings in the slip bodies 2| and the tongues 32 to removably secure the shoes 30 to the bodies 2|.Y The active pipe engaging faces of the shoes 30 are concaved to substantially conform to the pipe P. Gripping wickers or teeth 34 are provided on the active concaved surfaces of the shoes 30. It is preferred to pitch the teeth 34 at'a comparatively steep angle as illustrated in Fig. 5 to more effectively grip the object or pipe P. The wickers or teeth 34 being pitched in this manner dependably prevent relative rotation between the pipe and the slips without scoring or cutting the pipe and in the event the pipe suddenly drops or moves downwardly the sharply pitched teeth cushion the engagement of the pipe with the slips by effecting slight turning between them. In practice it has been found desirable to cut the wickers or teeth 34 with a six inch Ylead and a one quarter inch pitch. y i -f -35 having surfaces 36 flush with the wall of the bushing opening I'I. The surfaces 36 are preferably concaved and of the same cylindrical curv vature as the wall of the opening I'I. The bushing I0 having the members 35 occupying the lower portions of the slots I| presents a continuous annular face at the lower end of the opening I'I. The members 35 are preferably of hard material to be wear resisting. The stop members 35 are adapted to be arranged in the slots II after the slots have been ground or otherwise machined. In the typical construction illustrated the members 35 are welded to the bushing sections A and B at 31. Where one of the slots I I has its central vertical axis coincident with the plane I8, the member 35 in the said slot comprises two equal sections 35a, each secured to a section of the bushing III.

In operation the bushing sections A and B are arrangedv in the table T as shown in the drawings and the slips I2 may be readily slid in the slots II to engage and grip the pipe P. The slips I2 are entered in the upper ends of the slots I I and the surfaces 2|a assist in directing and guiding the slips into the slots. The cooperation of the slip faces 23 with the slot walls 20 urges the slips into gripping cooperation with the pipe and maintains the slips in proper engagement with the pipe. The full, extensive and evenly cooperating surfaces 23 and walls 20 prevent the slips I2 from rocking or tilting and maintain the slips in vertical positions where their shoes 30 have full even engagement with the pipe P. The cooperating surfaces 23 and walls 20 are long and extensive whereby the forces and pressures are well distributed. It is to be noted that the slips I2 have their major portions received in the slots I I and that the slips bear in the slots throughout the greater portions of their vertical extents, reducing wear. preventing the slips from jumping from the bushing and effectively distributing the forces to the bushing. In the event that the pipe P is to be turned or rotated by the table T the side surfaces 22 of the slip bodies 2| have extensive cooperation with the flat side walls of the slotsI II so .that the slips dependably transmit the rotation to the pipe P. The shoes 30 take all the wear resulting from the engagement with the pipe P and the shoes may be easily replaced when worn. Shoes 30, intended for gripping pipe and other objects of various diameters, may be readily provided on the slips I2 to adapt the assembly for the handling of various objects.

The stop members 35 in the lower ends of the slots I I operate to prevent the slips I2 from passing downwardly from the slots and falling into the well. The members 35 close the lower ends of the slots II to prevent the pipe P and couplings and joints on the pipe from entering the slots II and from wearing and breaking away the bushing parts at the slots. In many cases the pipe P or object extending through the bushing I0 is off center in theopening I'I so that it bears on the wall of the opening and when the pipe is lowered or raised its joints and couplings strike the bushlI I) ing at the ends of the opening. The members 35 in fully occupying the lower ends of the slots Il provide the bushing I with a continuous annular surface at the lower end of its opening l'l so that the joints and couplingson the pipe do not wear away or break off the bushing parts defining the slots Il Fig. 6 of the drawings illustrates a slightly modied form of slip and bushing assembly. In accordance with the form of the invention illustrated in Fig. 6 of the drawings the bushing |61* is separated or divided at a vertical plane lfJ into two unequal sections A1 and B1. The plane of division 40 of the bushing lllEL is offset or spaced from the central vertical axis of the bushing whereby the section A1 is considerably larger than the section B1. The plane of division or separation 40 is tangential to a circle somewhat smaller in diameter than the bushing opening Ha whereby the opening I'Ia has a portion at the inner side of the small section B1. The bushing opening Il'al is cylindrical or of uniform diameter and is provided with circumferentially spaced slots llla to receive slips |22. There are preferably three equally spaced slots lla provided in the bushing Illa. The slots I Ia are spaced and related so that one slot is provided in the section B1 and two spaced slots occur in the section A1. The bushing l0a may be identical with the bushing l0 except for the structure just described and the slots I la and the slips l2a may be identical with the slots and slips of the previously described form of the invention. The slot Il11 in the bushing section B1 is positioned so that its side walls are substantially normal to the plane of separation 40 of the bushing. In the assembly illustrated in Fig. 6 two of the slips I2a are carried by a single one piece section A1 so that there is no working or spreading of the bushing parts carrying these two slips. The operation of the assembly illustrated in Fig. 6 of the drawings is the same as the operation of the form of the invention illustrated in Figs. 1 to 5, inclusive, of the drawings.

Having described only typical preferred forms and applications of my invention, I do not wish to be limited or restricted to the specific details herein set forth, but wish to reserve to myself any Variations or modiications that may appear to those skilled in the art or fall within the scope or the following claims.

Having described my invention, I claim:

l. A rotary table bushing comprising, two substantially equal sections, there being an opening between the sections whose longitudinal axis is in the plane of separation of the sections and circumferentially spaced slots in the wall of the opening for receiving slips, one of said slots hav ing its central vertical axis coincident with the plane of separation of the sections.

2. A rotary table bushing comprising, a body having two substantially equal sections, there being a substantially central opening in the body of uniform diameter and three equally circumferentially spaced slots in the wall of the opening for receiving slips; one of said slots having its central vertical axis coincident with the plane of division of the body.

V3. A rotary Atable bushing comprising, a body having two unequal sections, there being a central vertical opening in the body and three equally spaced vertical slots' in the wall of the opening for receiving slips, two of said slots being in the larger body section, and the third slot being in the smaller body section.

4. In an assembly of the character described, a gripping slip comprising, a body having an in clined inner surface and a vertical outer side, there being a dove-tailed groove in the said outer side of the body, said groove having a lower wall pitched upwardly and toward said outer side, a replaceable shoe at said outer side, and a dovetailed tongue on the shoe cooperating with the groove, the tongue having a lower end pitched upwardly and toward said outer side to have locking cooperation with the said lower wall.

DENNIS L. DRISCOLL. 

